Add support for park and ride itineraries when calculating CO2 emissions

src/ext-test/java/org/opentripplanner/ext/emissions/EmissionsTest.java

@@ -82,7 +82,7 @@ void testGetEmissionsForCarRoute() {
   @Test
   void testNoEmissionsForFeedWithoutEmissionsConfigured() {
     Itinerary i = new Itinerary(List.of(createTransitLeg(ROUTE_WITHOUT_EMISSIONS_CONFIGURED)));
-    assertEquals(null, emissionsFilter.filter(List.of(i)).get(0).getEmissionsPerPerson());
+    assertNull(emissionsFilter.filter(List.of(i)).get(0).getEmissionsPerPerson());
   }
 
   @Test

src/ext/java/org/opentripplanner/ext/emissions/EmissionsFilter.java

@@ -30,10 +30,7 @@ public List<Itinerary> filter(List<Itinerary> itineraries) {
         .map(TransitLeg.class::cast)
         .toList();
 
-      calculateCo2EmissionsForTransit(transitLegs)
-        .ifPresent(co2 -> {
-          itinerary.setEmissionsPerPerson(new Emissions(co2));
-        });
+      Optional<Grams> co2ForTransit = calculateCo2EmissionsForTransit(transitLegs);
 
       List<StreetLeg> carLegs = itinerary
         .getLegs()
@@ -43,20 +40,17 @@ public List<Itinerary> filter(List<Itinerary> itineraries) {
         .filter(leg -> leg.getMode() == TraverseMode.CAR)
         .toList();
 
-      calculateCo2EmissionsForCar(carLegs)
-        .ifPresent(co2 -> {
-          if (transitLegs.isEmpty()) {
-            itinerary.setEmissionsPerPerson(new Emissions(co2));
-          } else if (
-            itinerary.getEmissionsPerPerson() != null &&
-            itinerary.getEmissionsPerPerson().getCo2() != null
-          ) {
-            // Calculate park and ride emissions.
-            itinerary.setEmissionsPerPerson(
-              new Emissions(itinerary.getEmissionsPerPerson().getCo2().plus(co2))
-            );
-          }
-        });
+      Optional<Grams> co2ForCar = calculateCo2EmissionsForCar(carLegs);
+
+      if (
+        co2ForTransit.isPresent() ||
+        co2ForCar.isPresent() &&
+        (transitLegs.isEmpty() || co2ForTransit.isPresent())
+      ) {
+        Grams co2 = co2ForTransit.isPresent() ? co2ForTransit.get() : new Grams(0);
+        co2 = co2ForCar.isPresent() ? co2.plus(co2ForCar.get()) : co2;
+        itinerary.setEmissionsPerPerson(new Emissions(co2));
+      }
     }
     return itineraries;
   }